Although from what I'm reading, having improved my google-fu, it seems as though it's a case-by-case basis. Some find it offensive (and they never give a reason why) and some don't. I've yet to encounter anything that says that "voice-off" is the preferred term, only that at least some Deaf people think "mute" is offensive. If I'm picking up on context clues correctly, the deaf people who find mute offensive can talk, so maybe they're simply offended that people think
they're mute just because they're deaf.
Given that there's so much documentation that implies "Mute" isn't offensive, I'm surprised there hasn't been more talk on the matter; every time I've searched the web I come across this very thread.
Then I come across this little number: http://www.ellasflashlight.com/?p=8
Which is a vlog written by a woman who is deaf and cannot speak, she claims the sign for "Deaf" is actually literally translated as "Deaf-mute"
"a literal translation of the common sign for DEAF, the index finger covering the ear, then covering the mouth, is DEAF-MUTE…yes, that’s the root meaning, so literally many of us have been saying we are “Deaf mutes” proudly for a long time"
So I just don't even know what to think anymore. Still can't find any institutions organized by the Deaf community that claim "mute" is offensive when it is used correctly, but since there are a fair number of deaf people who take offense, I wont use it when dealing with the Deaf community anymore, despite the fact that it's never been a problem in the past.